From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54397) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXQwB-0003EV-7J for qemu-devel@nongnu.org; Mon, 16 Mar 2015 05:03:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YXQwA-0000Ob-B7 for qemu-devel@nongnu.org; Mon, 16 Mar 2015 05:03:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42495) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXQw9-0000OO-Pi for qemu-devel@nongnu.org; Mon, 16 Mar 2015 05:03:50 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t2G93mv4009926 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Mon, 16 Mar 2015 05:03:48 -0400 From: Fam Zheng Date: Mon, 16 Mar 2015 17:03:36 +0800 Message-Id: <1426496617-10702-5-git-send-email-famz@redhat.com> In-Reply-To: <1426496617-10702-1-git-send-email-famz@redhat.com> References: <1426496617-10702-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v4 4/5] exec: Notify cpu_register_map_client caller if the bounce buffer is available List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini The caller's workflow is like if (!address_space_map()) { ... cpu_register_map_client(); } If bounce buffer became available after address_space_map() but before cpu_register_map_client(), the caller could miss it and has to wait for the next bounce buffer notify, which may never happen in the worse case. Just notify the list in cpu_register_map_client(). Signed-off-by: Fam Zheng --- exec.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/exec.c b/exec.c index 9f6c4f8..0fa7487 100644 --- a/exec.c +++ b/exec.c @@ -2489,6 +2489,18 @@ QemuMutex map_client_list_lock; static QLIST_HEAD(map_client_list, MapClient) map_client_list = QLIST_HEAD_INITIALIZER(map_client_list); +static void cpu_unregister_map_client(void *_client); +static void cpu_notify_map_clients_locked(void) +{ + MapClient *client; + + while (!QLIST_EMPTY(&map_client_list)) { + client = QLIST_FIRST(&map_client_list); + client->callback(client->opaque); + cpu_unregister_map_client(client); + } +} + void *cpu_register_map_client(void *opaque, void (*callback)(void *opaque)) { MapClient *client = g_malloc(sizeof(*client)); @@ -2497,6 +2509,9 @@ void *cpu_register_map_client(void *opaque, void (*callback)(void *opaque)) client->opaque = opaque; client->callback = callback; QLIST_INSERT_HEAD(&map_client_list, client, link); + if (!atomic_read(&bounce.in_use)) { + cpu_notify_map_clients_locked(); + } qemu_mutex_unlock(&map_client_list_lock); return client; } @@ -2521,14 +2536,8 @@ static void cpu_unregister_map_client(void *_client) static void cpu_notify_map_clients(void) { - MapClient *client; - qemu_mutex_lock(&map_client_list_lock); - while (!QLIST_EMPTY(&map_client_list)) { - client = QLIST_FIRST(&map_client_list); - client->callback(client->opaque); - cpu_unregister_map_client(client); - } + cpu_notify_map_clients_locked(); qemu_mutex_unlock(&map_client_list_lock); } -- 1.9.3